The present invention relates to work rolls for use in rolling apparatus for producing articles of deformed cross section, such as flat heat exchange tube component members, heat sinks and lead frames, from a metal blank sheet.
For example, component members of flat heat exchange tubes which comprise a flat plate portion and a plurality of upright walls formed on one surface of the plate portion integrally therewith and arranged as spaced apart from one another are produced by passing a metal blank sheet through a rolling apparatus wherein one of work rolls has a plurality of upright wall shaping annular grooves formed in the peripheral surface of the roll over the entire circumference thereof as is already known (see JP-A No. 182928/1997).
Conventionally used as such a work roll for rolling apparatus is one comprising a hollow cylindrical body which is integrally formed in its entirety and has a plurality of upright wall shaping annular grooves formed in its outer peripheral surface. The annular grooves are formed by subjecting the outer peripheral surface of the integrally formed cylindrical body to cutting, grinding and electrical discharge machining operations, and subsequently polishing the inner peripheral surfaces of the annular grooved portions to smooth finishes and obtain the conventional work roll.
However, the conventional work roll described has the following problems. In the case where the upright walls of the component member to be produced for the flat heat exchange tube have a small thickness and a great height, the upright wall shaping annular grooves have a small width and a great depth, whereas difficulties are then encountered in forming the annular grooves by cutting, grinding and electrical discharge machining and also in finishing the inner peripheral surfaces of the annular grooved portions by polishing. Accordingly, the fabrication of the entire work roll requires cumbersome work, a prolonged period and an increased cost. Moreover, since the inner peripheral surfaces defining the annular grooves are difficult to finish by polishing, the grooved inner peripheral surfaces are finished with low accuracy giving an impaired surface quality to the heat exchange component member obtained. Further if the work roll becomes locally worn or damaged, there arises a need to produce the entire work roll anew for replacement, consequently necessitating a prolonged period of time and an increased cost for the production and replacement of the work roll.
Especially in the case where it is required to form cutouts in the upper edges of the upright walls of the heat exchange tube component member to be produced, there is a need to form cutout shaping projections on the bottom surfaces of the annular grooved portions of the work roll. This presents difficulties in machining the grooved portions and finishing the peripheral surfaces of the projections, necessitating more cumbersome work for producing the work roll in its entirety, a further extended period for the production and a higher production cost. Additionally, the projection surfaces will be finished with lower accuracy to give an impaired quality to the cutout surfaces.
An object of the present invention is to overcome the foregoing problems and to provide a work roll which is easier to make and which is given higher surface finish accuracy than conventionally for use in rolling apparatus.
The present invention provides a work roll for rolling apparatus which comprises different kinds of disks having different diameters and arranged on an axis into juxtaposed layers as secured to one another, the disks of each kind being used in a specified number, each of the disks having an outer peripheral surface serving as a working surface.
When thus constructed, the work roll can be fabricated by making the individual disks, arranging the disks into juxtaposed layers and securing the disks to one another. Since the individual disks can be produced more easily than the conventional work roll, the roll can be produced within a shortened period of time at a lower cost. Since the peripheral surfaces of the individual disks can be finished by polishing easily, the surfaces can be finished with improved accuracy to give an excellent surface quality to the product obtained. Further even if one of the disks becomes locally worn or damaged, the worn or damaged disk only needs to be replaced by a corresponding disk which alone is to be prepared anew. This shortens the time required for the replacement and results in a reduced cost.
The work roll of the invention is used in a rolling apparatus for producing an article having a deformed cross section and comprising a plate portion, and a plurality of upright walls formed on one of opposite surfaces of the plate portion integrally therewith and arranged as spaced apart from one another. In this case, large disks are arranged at respective portions not forming the upright walls, and small disks smaller than the large disks in radius by an amount corresponding to the height of the upright walls are arranged at respective portions for forming the upright walls.
When the article of deformed cross section to be produced and comprising a plate portion, and a plurality of upright walls formed on one of opposite surfaces of the plate portion integrally therewith and arranged as spaced apart from one another must be formed with cutouts in the upper edges of the upright walls, the outer peripheral surfaces of the small disks are formed with projections for shaping the cutouts. To form the projections, the small disks can be machined more easily than when the bottom surfaces of the annular grooved portions of the cylindrical body are machined to form the cutout shaping projections in producing the conventional work roll. Moreover, the peripheral surfaces of the projections can be finished also easily. Accordingly the work of producing the work roll in its entirety is not very cumbersome as compared with the case wherein no projections are formed on the small disks, consequently necessitating only a slightly longer period for the fabrication of the work roll and a slightly increased production cost. Since the peripheral surfaces of the projections are easy to finish, the finished surfaces have improved accuracy to give an excellent quality to the interior surfaces defining the cutouts.
The present invention provides a rolling apparatus which comprises a central work roll and a plurality of planetary work rolls arranged around the central work roll and spaced apart cicumferentially thereof, at least one of the central work roll and the planetary work rolls being one of the work rolls of the invention described.
The invention further provides a rolling apparatus which comprises two work rolls in a pair, at least one of the two work rolls being one of the work rolls of the invention described.